django:doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS.

启动django 时，报错如下：
RuntimeError: Model class addresstest.models.address_info doesn't declare an explicit app_label and isn't in an application in INSTALLED_APPS.
 

需要在 settings.py 中的INSTALLED_APPS 添加 app包名称： addresstest

解决方案：

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'addresstest',
]